Buggy code:
public final class LoggingEventFieldResolver { public static final List keywordList = new ArrayList ( ) ; public static final String LOGGER_FIELD = "LOGGER" ; public static final String LEVEL_FIELD = "LEVEL" ; public static final String CLASS_FIELD = "CLASS" ; public static final String FILE_FIELD = "FILE" ; public static final String LINE_FIELD = "LINE" ; public static final String METHOD_FIELD = "METHOD" ; public static final String MSG_FIELD = "MSG" ; public static final String NDC_FIELD = "NDC" ; public static final String EXCEPTION_FIELD = "EXCEPTION" ; public static final String TIMESTAMP_FIELD = "TIMESTAMP" ; public static final String THREAD_FIELD = "THREAD" ; public static final String MDC_FIELD = "MDC." ; public static final String PROP_FIELD = "PROP." ; public static final String EMPTY_STRING = "" ; private static final LoggingEventFieldResolver resolver = new LoggingEventFieldResolver ( ) ; private LoggingEventFieldResolver ( ) { } public String applyFields ( String replaceText , LoggingEvent event ) { } public static LoggingEventFieldResolver getInstance ( ) { } public boolean isField ( String fieldName ) { } public Object getValue ( String fieldName , LoggingEvent event ) { String upperField = fieldName . toUpperCase ( ) ; LocationInfo info = null ; if ( event . locationInformationExists ( ) ) { info = event . getLocationInformation ( ) ; } if ( LoggingEventFieldResolver . LOGGER_FIELD . equals ( upperField ) ) { return event . getLoggerName ( ) ; } else if ( LoggingEventFieldResolver . LEVEL_FIELD . equals ( upperField ) ) { return event . getLevel ( ) ; } else if ( LoggingEventFieldResolver . CLASS_FIELD . equals ( upperField ) ) { return info == null ? LoggingEventFieldResolver . EMPTY_STRING : info . getClassName ( ) ; } else if ( LoggingEventFieldResolver . FILE_FIELD . equals ( upperField ) ) { return info == null ? LoggingEventFieldResolver . EMPTY_STRING : info . getFileName ( ) ; } else if ( LoggingEventFieldResolver . LINE_FIELD . equals ( upperField ) ) { return info == null ? LoggingEventFieldResolver . EMPTY_STRING : info . getLineNumber ( ) ; } else if ( LoggingEventFieldResolver . METHOD_FIELD . equals ( upperField ) ) { return info == null ? LoggingEventFieldResolver . EMPTY_STRING : info . getMethodName ( ) ; } else if ( LoggingEventFieldResolver . MSG_FIELD . equals ( upperField ) ) { return event . getMessage ( ) ; } else if ( LoggingEventFieldResolver . NDC_FIELD . equals ( upperField ) ) { String ndcValue = event . getNDC ( ) ; return ndcValue == null ? LoggingEventFieldResolver . EMPTY_STRING : ndcValue ; } else if ( LoggingEventFieldResolver . EXCEPTION_FIELD . equals ( upperField ) ) { return ( event . getThrowableStrRep ( ) ) == null ? LoggingEventFieldResolver . EMPTY_STRING : getExceptionMessage ( event . getThrowableStrRep ( ) ) ; } else if ( LoggingEventFieldResolver . TIMESTAMP_FIELD . equals ( upperField ) ) { return new Long ( event . timeStamp ) ; } else if ( LoggingEventFieldResolver . THREAD_FIELD . equals ( upperField ) ) { return event . getThreadName ( ) ; } else if ( upperField . startsWith ( LoggingEventFieldResolver . MDC_FIELD ) ) { Object mdcValue = event . getMDC ( fieldName . substring ( 4 ) ) ; return mdcValue == null ? LoggingEventFieldResolver . EMPTY_STRING : mdcValue . toString ( ) ; } else if ( upperField . startsWith ( LoggingEventFieldResolver . PROP_FIELD ) ) { String propValue = event . getProperty ( fieldName . substring ( 5 ) ) ; return propValue == null ? LoggingEventFieldResolver . EMPTY_STRING : propValue ; } <START_BUG> throw new RuntimeException ( ( "Unsupported<seq2seq4repair_space>field<seq2seq4repair_space>name:<seq2seq4repair_space>" + fieldName ) ) ; <END_BUG> } private String getExceptionMessage ( String [ ] exception ) { } }

Fix:
throw new IllegalArgumentException ( ( "Unsupported<seq2seq4repair_space>field<seq2seq4repair_space>name:<seq2seq4repair_space>" + fieldName ) ) ;